A recent story of contact tracing in rural Illinois illustrates how a single community gathering can lead directly to infections in a skilled nursing facility, and the challenges associated with reopening to public events.

In early February 2021, the Illinois Health Department received word that COVID-19 infections had suddenly doubled in a rural county. Staff members were sent to perform routine contract tracing, and identified a cluster of cases linked to an indoor opening event at a bar. Infections were found among people who had either attended the event or who had close contact with an attendee during the 14 days before they noticed symptoms, or the testing date.

One bar opening attendee was a certified nursing assistant who worked at an area long-term care facility. This person was asymptomatic, but tested positive for COVID-19 when the facility performed routine testing four days after the event. This spurred the facility to test all residents and staff members, and it found secondary cases in one staff member and two residents who had close contact with the CNA, reported Wayne A. Duffus, M.D., Ph.D., of the Illinois Department of Public Health.

The result was that one resident was hospitalized on Feb. 20, within 14 days of testing positive for COVID-19. The resident was discharged the same day. All four infected staff members and residents previously had been offered the COVID-19 vaccine, but none had been vaccinated, Duffus and colleagues wrote.

Among the 29 people known to have worked at or attended the bar opening, four reported having had COVID-19–like symptoms on the day of the event. It is known that the bar was not open to outside air, but information was not collected on whether patrons and staff members were practicing COVID-19 mitigation measures. In addition, interviews were voluntary, and it is unlikely that all secondary cases were counted, so the full extent of the outbreak is unknown, the authors noted.

The outbreak also led to secondary cases among household and school contacts, resulting in one school closure that affected 650 students.

The findings provide a snapshot of the issues faced by public health officials and business owners attempting safe reopenings during the pandemic, the authors wrote. Businesses can work with local health officials to promote behaviors and maintain environments that reduce the risk for SARS-CoV-2 transmission, they concluded. 

Full findings were published April 5 in the CDC’s Morbidity and Mortality Weekly Report.